Bad Piggies Ground Hog Day Bonus Level 1-V (1-5) is 3-starred in two steps. First, navigate your contraption all the way up through the star box on the hill. Then let it roll back to cross the finish line. Now build a smaller contraption with the tnt box. Let it roll down the hill, and detonate the tnt at the first ravine. This should send the pig rolling down towards the finish line within the time limit.
If you have a different strategy for completing this level feel free to leave a comment below.